Cable protector



Feb. 4,.1941. P. 1'. coFFiN ETA-1.

CABLE PROTECTOR Filed June 6. 1938 1NVENTORS PH/L/P 7. -CU/-F//v MAXWELL E /1/0 YES ATTORNEY.

Patented Feb. 4, 1941 l 2,230,611 A UNITED STATESv miriam"l OFFICE CABLE PROTECTOR ,Philip T. Collin, Gien Ridge, N. I., and Maxwell E. Noyes, Pittsburgh, Pa., asslgnors to Aluminum Company of America, Pittsburgh, Pa., a corporation o! Pennsylvania Application June 6, 1938, Serial No. 211,980

4 Claims. (Cl. 248-63) This invention relates to protecting devices between it and the cable protector, and there is for electrical transmission lines, and more paralso wear on the portion of the protector which ticularly to cable protectors consisting of a helirests onV the support or insulator. cally shaped wire or rod, in combination with a l A further diiilculty encountered is that it is 5 5 transmission line cable. awkward to apply helical protectors of the type It is Well known that suspended wires or cables, described above to transmission lines, because such as are commonly used in electrical transthey are not provided with any convenient pormission lines, are subject to breaking caused by tion which can be gripped by a person applying bending stresses induced by vibration of the wires them to the line. The helical shape of the pro- 10 or cables. The vibration is caused by transverse tector renders it difiicult to serve it around the air currents, and results in loops and nodes ocline quickly and securely. curring along the conductor. The most frequent It is an object of our invention to provide a failures in transmission lines resulting from vihelical cable protector which will overcome the bration occur at or near the points of support of above-mentioned objections. It is a further obu l5 the conductors. In an effort to overcome the ject of this invention to provide a pre-formed deleterious effects of vibration, numerous devices helical cable protector which is in tensional enhave been proposed for checking or damping the gagement with the transmission line on either vibration and for protecting the conductors at side of the support for the cable, but which is zo their pointsof support. provided with an intermediate portion which is 20 One type oi cable protector which has met free from engagement with the cable. It is a with some success consists of a rod or bar of further object of our invention to provide a premetal which helically encircles the transmission formed helical cable protector which will serve line cable at and adjacent the point of support, as a support for the transmission line cable to 25 and which is in intimate engagement with the which it is applied. Other objects of our inven- 25 cable throughout the length of the protector. tion will be apparent from the following specili- Sueh acable protector is pre-shaped by wrapping cation and claims, and from the accompanying a malleable metal rod or bar about a mandrel drawing, in which: which has a diameter slightly smaller than the Fig. 1 is a view in side elevation of a portion :o diameter of the wire or cable to which it is to be of a. transmission line to which is applied one 3o applied, giving it a permanent set. It is then form of a pre-formed helical cable protector conremoved from the mandrel and applied to a structed in accordance with our invention; transmission line by distending the helices of Fig. 2 is a sectional view taken on the line the device within their yield point, beginning at II-II of Fig. 1;

u one end of the protector and proceeding toward Fig. 3 is a view in side elevation oi a modica- 35 the other end, so that they encircle the line and tion of the device shown in Fig. 1, in which the grip it tightly. The protector is then in tenprotector serves to support the cable; sional engagement with the line. Such a device Fig. 4 is a view in side elevation of another l serves to distribute the stresses resulting from modification of our invention in operative posithe ilexing of the line, reduces the amplitude of tion on a transmission line supported by an invibration, and leng'tnens the life of the conductor. sulator; and 40 However, such devices are subject to certain Fig. 5 is a view in side elevation of the cable difficulties and disadvantages, particularly when protector shown in Fig. 4, partly applied to the employed on transmission lines using certain transmission line.

types of supports or insulators. When the sup- Referring to Figs. 1 and 2 of the drawing, the

4 ports or insulators are designed to be in contact transmission line cable I is supported by hook 2 4 with any considerable portion o! the conductor, having a. relatively wide bearing surface, which as where the conductor is intended to lie in a is attached by suitable means (not shown) to the groove in the support or insulator, the protector pole which carries the line. A one-piece helical so encircling the line rests on the groove ofthe cable protector 3 in the form of a pre-formed 50 support or insulator, and as a result there is an rod tightly encircles the cable l on either side accumulation o! bending stresses in the conducof the hook 2, the helical portions being in tentor at the points of contact with the support. sional engagement with the portion of the line The bending stresses are concentrated at those which they encircle. The tensional engagement points. Furthermore, there is increased wear on of the helical portions of the protector with the 5 the conductor at those points, caused by friction line results from the fact that the original bore u of the protector, before it is applied to the cable I, is slightly smaller than the diameter o! the transmission cable. Intermediate its ends. the helical configuration of the protector is interrupted to provide an arch or loop 4 which may be fastened to the hook 2 by means of bolts 5 or other suitable fastening means. Each end of the protector is provided with extended portions 6 Which project away from the cable and may be gripped readily by a person applying or removing the protector. Such a protector serves to reduce the amplitude of vibration of the cable and to distribute the bending stresses caused by the vibration.

Fig. 3 discloses a modification of my invention in which the protector 3 in the form of a preformed rod acts as a support for the transmission line cable l, as well as serving to minimize the eiect of vibration of the cabl. In this modification, the helical configuration of the protector is interrupted intermediate the ends thereof to provide an intermediate portion which is twisted to provide a loop 1 which can be attached by suitable means (not shown) to the pole which carries the cable. It will be readily seen that a cable protector of this construction serves in place of the usual suspension clamp, in addition to reducing the elect of bending stresses in the cable.

The modication shown in Fig. 4 is designed to render helical cable protectors more effective when used on transmission cables supported by the pin type of insulators. In Fig. 4, the transmission lin'e cable I is supported by an insulator 9 having a groove at the top thereof in which the cable rests, and in which the cable is held by a tie wire I attached to the cable and the insulator 9. An arch 8 is provided in the protector intermediate the helical portions thereof, and is so disposed as to extend over the insulator 9 and tie wire I0. When a helical protector is so constructed, the bending stresses in the conductor are not concentrated at the insulator, as is the case when the protector encircles the portion of the cable which lies in the groove of the insilator, as a result of the necessary contact be tween the protector and the insulator groove. Consequently, the effect of the bending stresses created by vibration of the cable is minimized, and the objectionable features previously mentioned as accompanying helical cable protectors are avoided.

To illustrate the manner in which pre-formed helical cable protectors are applied to transmission lines, Fig.,5 shows as partly applied to a line a protector of the type illustrated in Fig. 4, and described hereinabove.

It will be understood that various modifications can be made in the abovedescribed improvements without departing from the spirit of the invention and from the following claims.

We claim:

l. In combination with a transmission line cable or the like, a cable protector comprising a rod pre-formed into spaced helical gripping portions of a smaller original bore than the diameter of the cable and applied along the cable on both sides of aV means of support therefor, said rod Ameans for holding the protector in engagement with the cable, all whereby concentrations of vibration-induced bending stresses in the cable adjoiningv the means of support are materially suppressed.

2. In combination with a transmission line cable or the like, a cable protector comprising a rod pre-formed into spaced helical gripping portions of a smaller original bore than the diameter of the cable and applied along the cable on both sides of a means of support therefor, said rod being otherwise out of engagement with, and spaced from, said cable adjacent the means of support, said supporting means-comprising a section of said protector free from engagement with said cable and intermediate saidhelical portions, and said gripping portions throughout their length being self-maintained in tensonal engagement with the cable by rea-son of distention of said portions, and constituting the sole means for holding the protector in engagement with the cable, all whereby concentrations of vibrationinduced bending stresses in the cable adjoining the means ofsupport are materially suppressed.

3. In combination with a transmission line cable or the like, a hook supporting said cable, and a cable protector comprising a rod preformed into spaced helical gripping portions of a smaller original bore than the diameter of the cable and applied along the cable on both sides of said hook, said rod being otherwise out of engagement with, and spaced from, said cable adjacent said hook, and said gripping portions throughout their length being in self-maintained tensonal engagement with the cable by reason of distention of said portions, and said gripping portions and said hook constituting the sole means for holding the protector in engagement with the cable, all whereby concentrations of vibration-induced bending stresses in the cable adjoining the hook are materially suppressed.

4. In combination with a transmission line cable or the like, a cable protector comprising a rod pre-formed into spaced helical gripping portions of a smaller original bore than the diameter of the cable and applied along the cable on both sides of a means of support therefor, said rod being otherwise out of engagement with, and spaced from, said cable adjacent the means of support, said means of support comprising a loop in said rod, and said gripping portions throughout their length being in self-maintained tensional engagement with the cable by reason of distention of said portions, and constituting the sole means for holding the protector in engagement with the cable, all whereby concentrations of vibration-induced bending stresses in the cable adjoining the hook are materially suppressed.

PHILIP T. COFFIN. MAXWELL E, NOYES. 

